The atomic force microscope (hereinafter “AFM”) developed in 1986 (see non-patent document 1), is the kind of microscope that enables high resolution observation of the surface structures of conductors, semiconductors and insulators (including polymers and biomaterials). By using the single-molecule measuring method (also called “force spectroscopy”) of the AFM, the inter-molecular interaction (intermolecular bonding strength) at single molecule levels (see non-Patent documents 2 and 3) and the intra-molecular interaction (conformation change of a single molecule) (see non-patent documents 4 and 5) can be examined.    Non-patent Document 1: G. Binnig, C. F. Quate, and Ch. Gerber, “Atomic Force Microscope”, Phys. Rev. Lett. Vol. 56, 1986, p. 930.    Non-patent Document 2: Frisbie, C. D., Rozsnyai, L. F., Noy, A., Wrighton, M. S. and Lieber, C. M. “Functional Group Imaging by Chemical Force Microscopy”, Science Vol. 265, 1994, p. 2071.    Non-patent Document 3: Lee, G. U., Kidwell, D. A. and Colton, R. J. “Sensing Discrete Streptavidin-Biotin Interactions with Atomic Force Microscopy”, Langmuir Vol. 10, 1994, p. 354-357.    Non-Patent Document 4: K. Mitsui, M. Hara, A. Ikai, FEBS Lett. “Mechanical unfolding of alpha2-macroglobulin molecules with atomic force microscope”, Vol. 385, 1996, p. 29.    Non-Patent Document 5: M. Rief, M. Gautel, F. Oesterhelt, J. M. Fernandez, H. E. Gaub, “Reversible Unfolding of Individual Titin Immunoglobulin Domains by AFM”, Science Vol. 276, 1997, p. 1109.